Fuel injected internal combustion engines have gained widespread acceptance as a fuel efficient alternative to conventional, carbureted engines. Fuel injected internal combustion engines are now electronically controlled by an on-board electronic control unit (ECU).
Fuel is supplied to the injectors (one for each cylinder in the engine) by plastic, or metal, fuel tubes, of round, square, or rectangular shape, commonly known as fuel rails. The fuel rails are adapted to receive the injectors, at spaced internals, to align same with the inlet port for each cylinder. The individual injectors may be retained on the fuel rail by clips, or other mechanical members. The fuel rails, with the depending injectors, are mated with the engine block, during the assembly process.
The mating of the fuel rail/injector subassembly, with the intake valves for the cylinders within the engine block, is relatively straightforward. However, when dealing with V-configured engines, such as V-6 or V-8 cylinder banks, greater difficulty is encountered. Angular adjustments, or corrections, made during assembling the fuel rail/injector subassembly to the engine block, are reflected in angular mismatching between the fuel rails and the rigid cross-over tube(s) joining same together. The mismatching is complicated by the production requirements of the assembly line, and by the cramped space available to work within, or under, the hood of the automobile.
The opposite ends of fuel rails are joined to rigid cross-over tubes associated with the supply, and return, sides, of the fuel system of the automotive vehicle. A representative fuel assembly (12) is shown in FIG. 1 of U.S. Pat. No. 5,002,030, granted Mar. 26, 1991, to Randall M. Mahnke, and assigned to the assignee of the instant application. The assembly (12) includes fuel rails (14, 16), cross-over tubes (28, 36), and pressure regulator (38); the flow path of the fuel is indicated by directional arrows (42, 44).
Quick, easily assembled, and reliable, connections must be established between the cross-over tubes and the fuel rails. Such connections must also be able to permit the cross-over tube to rotate relative to the longitudinal center-line of the fuel rail to compensate for any angular mismatch introduced during prior steps in the assembly process.
A known coupling (46) that addresses these problems is shown in FIG. 4 of U.S. Pat. No. 5,002,030. Such coupling functions in concert with annular flange (52) that is spaced inwardly of the terminal end (28a) of the cross-over tube (28); the end of the cross-over tube is inserted into an axial recess (48) in the fitting (46) retained in the end of the fuel rail (16). An O-ring (58) situated between the fitting and the annular flange seals the connection. The coupling (46) comprises a retainer (54) with an arcuately shaped flange (56) that provides a saddle support for the cross-over tube, and a bolt (55) connects the retainer to the end of the fuel rail. The bolt prevents axial separation of the components, but the cross-over tube may rotate freely relative to the fuel rail.
Another known coupling (46') is shown in FIG. 5 of U.S. Pat. No. 5,002,030. Such coupling includes a stepped fitting (60') that is inserted into the end of the fuel rail (16'); a stop (62') is formed at the inner end of the fitting, and a recessed surface (64') is formed near the entrance to the fitting. An annular flange (52') is formed on the cross-over tube. The terminal end (28a') of the cross-over tube (28') is inserted into the fitting, so that the inner end of the tube abuts the stop (62'). O-ring (65') fits into the recessed surface and cooperates with the annular flange to seal the coupling. A retaining flange (66'), at the entrance into the fitting, contacts the annular flange, and retains the components in cooperating relationship. Slight axial play is permitted between cross-over tube (28) and the fuel rail (16) is attainable, so that the O-ring seal (65') is not pinched. Consequently, the cross-over tube may be secured in the fitting, by crimping over flanges (67'); the cross-over tube may be rotated relative to the fuel rail, as noted in column 5, lines 10-41.
Whereas the couplings disclosed in U.S. Pat. No. 5,002,030, proved to be satisfactory in correcting for angular mismatches, such couplings require, and/or permit, a considerable degree of rotation between the cross-over tube and the fuel rail. The couplings utilize an annular flange on the cross-over tube to rotate upon an annular surface on the fitting inserted into the open end of the fuel rail. In some instances, wherein the engine compartment has reduced overhead, the degree of rotational movement of the cross-over tube must be reduced or curtailed, to suit the customer's demands, and existing couplings proved unable to meet the new operational criteria.
The known couplings required the assembly of several components, and each operation adds to the time and cost considerations relevant to high speed production, and assembly of automotive components. Simpler couplings are constantly sought for original equipment manufacture, as well as for the repair and/or replacement after-market.
Consequently, couplings with rotation limiting characteristics, which would permit rotational movement within prescribed limits, were sought. The limited extent of rotational movement would allow quick, accurate, and reliable couplings, even within sorely limited overhead space.